Skewed Bridge
The bridge has a 308'-long main span that is a heavily skewed, pin-connected, Baltimore thru truss with massive portal bracing. It is traditionally compose...
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The bridge has a 308'-long main span that is a heavily skewed, pin-connected, Baltimore thru truss with massive portal bracing. It is traditionally composed of built-up compression members and eye bar tension members. The approach spans are 20'-long T beams. The bridge is supported on concrete bents and abutments.
"The Baltimore truss, specifically, was designed by engineers of the Baltimore and Ohio Railroad in 1871. The truss was adapted for highway use as early as the 1880s, often for spans of modest lengths. When steel replaced wrought iron and rigid, riveted connections replaced pins in the early decades of the twentieth century, the Baltimore truss was used for longer span highway bridges until the 1920s. The Baltimore truss is basically a parallel chord Pratt with sub-divided panels in which each diagonal is braced at its middle with sub-diagonals and vertical sub-struts. The logic leading to subdivided panels stems from the need to maintain an economic spacing of floor beams in longer span bridges. As the distance between chords increases, so does the width of panels. In order to maintain optimum slope of diagonals (45 - 60 degrees) and, an economic spacing of floor beams, the panels were subdivided at intermediate points between the main vertical members. The Baltimore truss is significant for its association with the railroad. Highway bridges built using the Baltimore truss are not amongst the more common bridge types and are considered significant if they retain their character-defining features. Such features include the elements that comprise its form-basically it is Pratt with parallel top and bottom chords, but with generally wide, subdivided panels in which each diagonal is braced at its middle with sub-diagonals and sub-struts. The end posts are inclined. Character defining features include its parallel top and bottom chords, verticals and diagonals (including substruts or sub-ties), floor beams, stringers, struts, form of connection, and portal features (e.g., struts, bracing)." [From: A Context for Common Historic Bridge Types by Parsons Brinckerhoff, October 2005]
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"The Baltimore truss, specifically, was designed by engineers of the Baltimore and Ohio Railroad in 1871. The truss was adapted for highway use as early as the 1880s, often for spans of modest lengths. When steel replaced wrought iron and rigid, riveted connections replaced pins in the early decades of the twentieth century, the Baltimore truss was used for longer span highway bridges until the 1920s. The Baltimore truss is basically a parallel chord Pratt with sub-divided panels in which each diagonal is braced at its middle with sub-diagonals and vertical sub-struts. The logic leading to subdivided panels stems from the need to maintain an economic spacing of floor beams in longer span bridges. As the distance between chords increases, so does the width of panels. In order to maintain optimum slope of diagonals (45 - 60 degrees) and, an economic spacing of floor beams, the panels were subdivided at intermediate points between the main vertical members. The Baltimore truss is significant for its association with the railroad. Highway bridges built using the Baltimore truss are not amongst the more common bridge types and are considered significant if they retain their character-defining features. Such features include the elements that comprise its form-basically it is Pratt with parallel top and bottom chords, but with generally wide, subdivided panels in which each diagonal is braced at its middle with sub-diagonals and sub-struts. The end posts are inclined. Character defining features include its parallel top and bottom chords, verticals and diagonals (including substruts or sub-ties), floor beams, stringers, struts, form of connection, and portal features (e.g., struts, bracing)." [From: A Context for Common Historic Bridge Types by Parsons Brinckerhoff, October 2005]
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Jun, 2017Views
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Behind The Lens
Location
This photo was taken in Lima OhioTime
The photo was taken in the afternoon.Lighting
The day was sunny with these wonderful fluffy white cloudsEquipment
I used a Nikon D3100 and kit 18-55 lens with a circular polarizing filter.Inspiration
I saw this bridge from a distance when I was in the area on business with a collegue. I was intrigued with the appearance that the bridge was skewed. I decided to drive the 1.5 hours back to the bridge on the weekend to get a better look at the bridge. It did not disappoint.Editing
I did some adjustments in photoshop elements and did the NIK conversion to black and white.In my camera bag
Camera body, two kit lenses, cpl filter, and a 50mm prime lens.Feedback
I drove over the bridge several times, then walked across it to look at the structure from many different angles. I imagined from the begining that I would prefer this as a black and white photo so I looked for lots of light and dark contrasts. The bridge is definately all about the angles.
